Author Topic: Screwed -- what to do?  (Read 1710 times)

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Online blueskull

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Screwed -- what to do?
« on: February 11, 2020, 08:58:35 am »
Just stripped the thread of my laptop by over tighten the screw, and now it won't retain screws.
There are still thread teeth, and screws can still screw in, but won't retain enough force.

Be aware that the screw is fine, just the thread is literally screwed.
Is there a way to fix it without having to drill it larger, tap it and insert a helix preform?

I do not have access to proprietary adhesives like form-a-thread. I only have access to general purpose thread lockers and epoxies plus tapes.

Any suggestions?
 

Offline Ed.Kloonk

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Re: Screwed -- what to do?
« Reply #1 on: February 11, 2020, 09:00:53 am »
Plastic or metal?
 

Online blueskull

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Re: Screwed -- what to do?
« Reply #2 on: February 11, 2020, 09:05:48 am »
Plastic or metal?

Steel screw screwed up magnesium alloy thread :palm:.
 

Offline Muttley Snickers

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Re: Screwed -- what to do?
« Reply #3 on: February 11, 2020, 09:15:08 am »
As a temporary fix, a slither of teflon tape might be enough for the screw to get a grip, it can't hurt to try it anyway.
 

Online blueskull

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Re: Screwed -- what to do?
« Reply #4 on: February 11, 2020, 09:24:10 am »
As a temporary fix, a slither of teflon tape might be enough for the screw to get a grip, it can't hurt to try it anyway.

Just tried with two, four and six layers of teflon tape, nope, didn't work.

The tape got squeezed to the root of the screw and the thread didn't lock in.
 

Offline sokoloff

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Offline thinkfat

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Re: Screwed -- what to do?
« Reply #6 on: February 11, 2020, 09:45:19 am »
As a temporary fix, a slither of teflon tape might be enough for the screw to get a grip, it can't hurt to try it anyway.

Just tried with two, four and six layers of teflon tape, nope, didn't work.

The tape got squeezed to the root of the screw and the thread didn't lock in.

Teflon won't work. By design, it provides only little friction. Exactly not what you need when you want it to stick to stripped threads.
Everybody likes gadgets. Until they try to make them.
 

Offline Pinkus

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Re: Screwed -- what to do?
« Reply #7 on: February 11, 2020, 09:51:26 am »
a few thin stranded wires shall do.
« Last Edit: February 11, 2020, 10:02:16 am by Pinkus »
 

Online shakalnokturn

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Re: Screwed -- what to do?
« Reply #8 on: February 11, 2020, 10:10:01 am »
I'd try bunging the hole with one form or another of epoxy "repair putty" and re-drilling a small hole in that.
 

Online blueskull

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Re: Screwed -- what to do?
« Reply #9 on: February 11, 2020, 10:22:08 am »
I'd try bunging the hole with one form or another of epoxy "repair putty" and re-drilling a small hole in that.

I cant' find any epoxy specifically designed for thread repairing in China, and I don't want to wait 2 weeks for things to arrive on a slow boat. Whatever pain you guys have buying from China I have buying from abroad.

a few thin stranded wires shall do.

Will try and report back later.

Try Purple Loctite (222)

https://www.henkel-adhesives.com/us/en/insights/all-insights/blog/about-purple-threadlocker.html

If wires don't work, I'll go along this path.

Teflon won't work. By design, it provides only little friction. Exactly not what you need when you want it to stick to stripped threads.

True. If all fail, I'll try electrical tape.
 

Offline thinkfat

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Re: Screwed -- what to do?
« Reply #10 on: February 11, 2020, 10:24:30 am »
If you have thin solder wire around, might work, too. No-flux core preferred.
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Online blueskull

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Re: Screwed -- what to do?
« Reply #11 on: February 11, 2020, 10:58:05 am »
Wires didn't work, tried 3 strand twist and single strand, tied with tweezers from tip to root.

Electrical tape didn't work, tried one layer and two layers.

I'll try 222 anaerobic adhesive, and that's pretty the last resort.

Otherwise I guess I will have to go along the drill and tap route with helix inserts.
« Last Edit: February 11, 2020, 10:59:45 am by blueskull »
 

Offline tunk

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Re: Screwed -- what to do?
« Reply #12 on: February 11, 2020, 11:07:44 am »
Try to fill it with epoxy, drill a 1.5mm hole
and see if a 2mm selftapper screw will hold.
 

Online blueskull

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Re: Screwed -- what to do?
« Reply #13 on: February 11, 2020, 11:09:40 am »
Try to fill it with epoxy, drill a 1.5mm hole
and see if a 2mm selftapper screw will hold.

Will try later. Just ordered a bottle of 222 and let's see what happens.

If not, I'll try to do some epoxy casting based on a negative screw profile.

If it still doesn't work, I will have to drill and tap.
 

Online Ian.M

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Re: Screwed -- what to do?
« Reply #14 on: February 11, 2020, 11:57:21 am »
1. Start with a brand new screw of the correct diameter and thread. (because the old thread will be scratched and may jam in the epoxy)
2. Wax the screw thread by heating it and touching it to a candle, then wipe off all excess wax while its hot and finally reheat for a thin even film of wax on the surface.
3. Clean the hole thoroughly with Acetone and a Q tip, or if really small, a narrow strip of paper and a tooth-pick.
4. Mix up any metal or ceramic powder loaded epoxy you can get - basically any hardware store epoxy that isn't translucent, according to its instructions.  Don't be tempted to try to mix a very small amount as errors in mix ratio are more likely, and will weaken it significantly, so its better to mix too much and discard the excess.
5. Work the epoxy into the screw thread, fill the hole and push the screw into it, WITHOUT any board or cover or other part it normally holds.
6. Wipe off excess epoxy and make sure the screw is straight and centered
7. Wait 24H for the epoxy to fully cure. DO NOT touch it till its set.
8. Unscrew the screw from the thread formed in the epoxy. If its difficult to turn, briefly touch the head with a soldering iron to melt the wax.
10. File off any remaining excess epoxy with a small diamond rasp.

You should now have a reasonably strong formed thread in the hole to fit the original screw.
« Last Edit: February 11, 2020, 06:59:17 pm by Ian.M »
 
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Offline Shock

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Re: Screwed -- what to do?
« Reply #15 on: February 11, 2020, 12:12:41 pm »
If possible insert/poke baking soda into the hole, then put a drop of viscous super glue (cyanoacrylate, an acrylic resin) on top so it sucks inwards. It should set fairly quickly as the baking soda is a partial accelerator. It adds mechanical strength to the dried super glue so will allow you to tap a new thread with the existing screw.

Makes sense to practice first just don't overfill the baking soda you don't want to have to chisel it of, super glue is easier to scrape with a blade.
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Online blueskull

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Re: Screwed -- what to do?
« Reply #16 on: February 11, 2020, 12:27:24 pm »
Thanks for the tips. I'll try them once I get back to Shenzhen after it is safe to do so. I'm now at home with limited tools, not even standard tapping tools or epoxies.
If the thread lock method doesn't work, I'll have to wait till 17th.
 

Offline Messtechniker

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Re: Screwed -- what to do?
« Reply #17 on: February 11, 2020, 02:52:49 pm »
Probably won't work with very small holes:
Simply insert - ghetto style - a wood chip from matchstick.
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Offline dreamcat4

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Re: Screwed -- what to do?
« Reply #18 on: February 11, 2020, 03:42:41 pm »
i would blow compressed air in the hole to clear any existing debris. the if you wrap a brand new screw with a little fine filament 0000 wire wool (the finest) and coat it in loktite 277 thread locker. then that will be the bet you can do without drilling out, re-threading, using the next size up. for example if it was an m2 screw --> m2.5. or for an m2.5 screw then m3. Let us know how you get on. Actually i have a magnesium body dell laptop here and broke a chassis screw clean off. The entire body of the screw is still stuck in the shassis screw hole with no obvious way to get it out again... since its such small diameter. So yeah... not sure what it is with these mangesium chassis

 :-//
 

Offline MadTux

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Re: Screwed -- what to do?
« Reply #19 on: February 11, 2020, 03:47:50 pm »
Get some thread inserts, drill screwed screw holes to size and epoxy inserts into drilled screw holes.
That is how I would do it.
 

Online blueskull

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Re: Screwed -- what to do?
« Reply #20 on: February 11, 2020, 03:52:23 pm »
I just tried to insert a wood splinter in it and it worked!
I'll just leave it as is until I go back to Shenzhen with my tools available.
I'll then spend time on molding an epoxy thread insert.
Since I still want warranty on this laptop, I don't really want to drill it.
 
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Offline Gyro

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Re: Screwed -- what to do?
« Reply #21 on: February 11, 2020, 08:00:30 pm »
Wood has been used as a structural gap filler for fixings since time immemorial. It will probably do as a 'permanent' fix.  :)
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Offline chris_leyson

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Re: Screwed -- what to do?
« Reply #22 on: February 11, 2020, 08:22:55 pm »
Good tip from Ian M. If available for your thread size you could try Helicoil inserts. Might need a bit practice first on some scrap, I know I would. Good luck. Edit: Sorry Blueskull missed your post about the wood splinter, glad it worked, I will remeber that fix if I am ever in the same situation.
« Last Edit: February 11, 2020, 08:25:23 pm by chris_leyson »
 

Offline tkamiya

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Re: Screwed -- what to do?
« Reply #23 on: February 12, 2020, 12:37:27 am »
I do this myself when damage is minor.

Use a pin-head hammer and lightly tap the hole.  The idea is by thinning THAT area, just around the hole, metal will expand and some of it will migrate to the threaded area.  When re-screwing the hole, just go very gingerly.  It won't take any torque or it will trash the thread again.  But it will hold well enough that the screw won't fall out.
 

Offline BravoV

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Re: Screwed -- what to do?
« Reply #24 on: February 12, 2020, 05:49:42 am »
Wood has been used as a structural gap filler for fixings since time immemorial. It will probably do as a 'permanent' fix.  :)

Instead of wood chips, on metal screw hole, I used solder chips, as they're soft and malleable enough not to destroy the existing screw hole, but as gap filler that will grip strong enough the screw.

Its easy to clean as well.
 
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